The Steamboating Forum

When exhausting through the hull should it exhaust below the waterline?

No.... when shut off, a vacuum may form and the (salt?) water gets drawn into the engine.

Exhaust _above_ the water line.

- Bart

Also, more back pressure unless you don't want to listen to the exhaust. Also, exhausting up the stack can give you good draft enhancement.

Any reason you don't want to just exhaust into a keel condenser? You'd have better boiler water control and you could then steam in salt water or horribly muddy and fouled up areas.

Mike

I removed the up the stack set up since I added a feed heater. Too much water out he top of the stack. I guess out the back top corner of the Hull is where it will be.I'm not condensing but if I was where would the exhaust exit?

If you were condensing, the exhaust would not exit. It would go to the condenser and then back to the hot well. All very tidy. And some water in the stream after the feedwater heater would not be a problem.

(Makes me sound like a used car salesman)

Mike

Water in the steam up the stack gives us a shower, what happens to the pressure in the condenser? Doesn't the pulsing od the exhaust splash or pressurize the hot well? Sorry for the lack of intelligence, I guess this is why I'm not condensing.

All of the exhaust turns to liquid in the condenser. There might be some pulsations where the condensate enters the hot well but I haven't noticed any.

My system is very simple. The engine exhaust goes to the 5/8" pipe running along the keel in the water. (about six feet long?) There is a pickup tube at the lower (front) end of the condenser that dumps into the hot well. The hand pump and the engine driven pump feed from the hot well. Round and round. No condensate pump. I have a single expansion engine. There is a good deal of bickering about whether a vacuum pump is worth the hassle on our small engines. I dunno.

There is one added and handy complication. In my system, the output of the engine driven pump can go two ways. Either to the boiler or through a float valve in the hot well.

The theory (and practice) of this design is that the total amount of water in a condensing system is a constant. The only losses are leakage (minimized, we hope), possible burner atomizing, and whistle activity ( a great deal when Barbara is not on the boat!). If I regulate the level of the hot well, I am also regulating the level of the boiler. Voila!

If the boiler level creeps down due to losses, I just add some water to the hot well. Any feed water treatment should remain in the boiler (it is, by the way, a water purifier by its nature) so any TSP or such is only rarely added to the hot well. All of my oil separation is at the input and outputs of the hot well.

I've steamed closed (condensing) systems and open systems and I find that a closed system makes for a cleaner boiler. A short blow down at the end of the day to remove a bit of crud and I'm good to go. I bought some litmus paper at a garden store and I dip a strip in the hot well when I think of it just to make sure the pH hasn't gotten low (acid) for some reason. I believe we are shooting for around ten or so. There are others on here that know wildly more about this than I.

My personal practice is to blow my system down hot when I'm laying up for the Winter or planning a long tow just to save some weight. When I refill the next time I add a dollup (scientific term meaning that I pour it my palm and most of it makes into the hot well) of TSP. You'll know if you have added too much. The hot well foams like shaken beer!

All in all, I think a condensing system might be less hassle than you might imagine. It just runs and I don't worry about salt, oil sewage or lord knows what in the body of water I'm passing through.

Obviously I'm avoiding my chore list on a lazy morning. As Jack says, "Cheers".

Mike

I'll chime in to echo Lopez Mike's comments - the condenser w/ a float valve in the hotwell makes for much simpler, easier cruising. Even if you don't fit a vacuum pump (neither Mike nor I use one), the condenser, hot well and float really make things easy. The one contraindication is if you need to use lube oil continuously in your engine; this is problematic to separate from the condensate. I use the standard separate settling tank w/ oil-sorb sheets; this easily handles the small amount of oil I introduce into both the piston valve chest and the cylinder when laying up the engine.

- Bart

Mike, just so I get this straight, what you are saying is that your float-valve is really a self-regulating by-pass valve. There must also be some minimal evaporation losses from the hot-well, so you do still need to keep weather eye on the gauge-glass.

So the exhaust pressure pushes the condensate into the hotwell?

What my winter project will be then, is to route the exhaust pipe through my feedwater heater out the bottom of the hull, along the keel and back through the hull into the hotwell. Then my pump supply will come from the hotwell to my steam injector, hand pump and feed pump, through the pump through the economiser then into the bottom of the boiler?